ETHPM
- parse and validate packages.
- given a web3 instance provide access to contract factory classes
- given a web3 instance provide access to all of the deployed contract instances for the chain that web3 is connected to.
- validate package bytecode matches compilation output.
- validate deployed bytecode matches compilation output
- access to packages dependencies
- construct new packages
Web3
The Package
object will function much like the Contract
class provided by web3
. Rather than instantiating the base class provided by ethpm
, you will instead use a classmethod
which generates a new Package
class for a given package.
OwnedPackage = BasePackage.factory('/path/to/owned-v1.0.0.json')
Then, the OwnedPackage
can be instantiated with any web3
intance.
owned_package = OwnedPackage(web3)
A Package
class can only be directly constructed from the parsed package JSON. It can also be initialized with the package's URI or the local filesystem path to a package by using Package.from_file(path)
.
Contract Factories
Contract factories should be accessible from the package class but you must also provide a web3 instance.
Owned = OwnedPackage.get_contract_factory(web3, 'owned')
From a package instance, they are also available as properties.
Owned = owned_package.contract_factories.owned
In cases where a contract uses a library, the contract factory will have
unlinked bytecode. The ethpm
package ships with its own subclass of
web3.contract.Contract
with a few extra methods and properties related to
bytecode linking
>>> math = owned_package.contract_factories.math
>>> math.has_linkable_bytecode
True
>>> math.is_bytecode_linked
False
>>> linked_math = math.link_bytecode({'MathLib': '0x1234...'})
>>> linked_math.is_bytecode_linked
True
Note: the actual format of the link data is not clear since library names aren't a one-size-fits all solution. We need the ability to specify specific link references in the code.
Deployed Contracts
Deployed contracts are only available from package instances. The package
instance will filter the deployments
based on the chain that web3
is
connected to.
Accessing deployments is done with property access
package.deployed_contracts.Greeter
IPFS
We'll need a pluggable backend system for IPFS access. A built-in default one that defaults to using infura should be enough to get off the ground.
Lower priority but important will be ensuring that a user can configure connecting to their own IPFS node.
Verifying Things
The Package
class should verify all of the following things.
- Package json matches EthPM V2 Manifest Specification
- Included bytecode matches compilation output
- Deployed bytecode matches compilation output
Dependencies
The Package
class should provide access to the full dependency tree.
>>> owned_package.build_dependencies['zeppelin']
<ZeppelinPackage>
Testing Strategy
- Load and validate packages from disk.
- Access package data.
- Access contract factories.